Improvement in slide-valves



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THOMAS ADAMS `AND GEORGE JOHN ransom OE-NO. 5 DUKE STREET,

ADELPHI, ENGLAND.

Letters Patent No. 68,932, dated Sepia-:uber 17, 1867; patented 'in England February 15, 1866.

IMPROVEMENT 1N SLIDE-VALVES.

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.',lO ALL WHOM IT MAY CONCERN: i

Be it known that we, THOMAS ADAMS and GEORGE JOHN PARSON, bothof Adelphi, in the county of Middle' sex, England, have invented a new and useful 4Improvement in Steam Engines; and wedo hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the artto which our invention appertains to make and use the same, reference being had to the accompanying drawings, forming Figure 1 is a plan view of our slide-valvejvith the top plate or cover of the steam-chest' oil'.

Figure 2 is al central vertical section of lig. 1 through the line a: se, the valve being shown covering `both steam-ports. Y

F igpre 3 isa vertical sectional elevation of the valve constructed ou a some-what different plan, but involving lthe same method of producing an equilibrium of pressure.

Figure 44 shows a longitudinal section of a steam-cylinder with the piston'aud piston-rod'pa'ckedupon the same planof counteracting pressures or obtaining lateral pressure by forcing together wedgeshaped rings by pressure in opposite directions.' The force exerted through the gland at R R satmospheric pressure.

Similar letters of reference indicate corresponding parts in the several'gures.

The object of this improvement is to so construct a valve that there shall be au equilibrium of pressure thereon, or soi that the pressure on the upper side shall be balanced by the pressureon the under side of the valve toA the `extent of the surfaces exposed to such action; y and. it consists in inserting and xing in the central part of the valve, between the two ends thereof, a ring constructed with a flange on its outersideroverlthe top Vsurface of the valve, the top side of the-flange forming a fillet to work against the door ofthe valve-boxyand l l l of equal area with the bottom side of the ilange.' This ring is also'constructed and fitted so as to admit of an' equal area of steam space Vabove and below its inner part. By the insertion of a ring so constructed the steam from the boiler will be caused to act simultaneously on the bottom of the flange, (thereby pressing thering upward against the door of the valve-box,) and on the fillet or topof the ange of equal area, (thereby pressing the ring downward.) The steam from the boiler will 'thus be caused to act over an equal area between the door of the valve-box or the division-plate and the fillet or top of the flange, and between the bottom of the ange and the top of the valve, thereby-balancing the pressure on the outer part of the ring. The recess or steamspace at the top of the inner part of the ring is equal in area to that at the bottom of the same, and the ring is balanced by the pressure of the exhaust steam acting equally therein.

A represents the valve; 0,-vthe valve-rod secured to the bridle B. The inlet-port ofthe-steam-chest maybe made in any proper place, either upon the top or sides. E, the cylinder face. F F are the steam-ports in the cylindex` face. G is the exhaust through the door ofthe steam-chest. H is a ring inserted inthe valvcA for the purpose of eiectiug the required displacement of steam so as to cause a balance of steam pressure. This'ring His east larger than the cavity in the valve A. A piece, of say one-sixteenth of an inch, is-cut out of it. 'The ring is then drawn together at butt-joint, shown at L, tig. 1, and in that position bored andvturn'ed in the lathe to t its place in the valve. A steady-pin, l), fig. 2, is used to keep the butt-joint in the centre line of motion. Two small springs M M are inserted between the ring and valve in order to keep it up to the door of the steam-chest while steam is o. The ring H is provided withfa fillet, N, which works against the cover D, and the ring is recessed inside at O. The steam in the chest acts from the'boiler simultaneously under the llet or on the bottom of the flange, (thereby pressing the ring upward against the cover D,) and on the fillet 'or top ofthe flange of equal areathereby prcssing the ring downward. The steam being thus caused to act over an equal areabetween the cover D and the fillet or top of the ilange, and between-the bottom of the flange andthe top of thevalve, thereby balancesthe pressure upon the outer part of the ring, or, in other. words, the steam being allowed to act under the fillet, and exerting its influence between the top side of the fillet and the cover, is held in an equilibrium of pressures. The ring H being recessed at O, tbc exhaust pressure of a high-pressure engine and the vacuum'of a low-pressur engine act equally en the top and bottom sides, holdingit in au equilibrium of pressure. The recesses a a inthe face of the valve are for the purposeof maintaining the lm of steam on the bars during high grades of expansion, also serving the purpose of lubrication by'steam. Fig. 3 shows a valve constructed on the saine principle as the one described, but on a different plan. This principle of balancing the opposite surfaces which are ezposed to the action of steam may also be employed with good e`ect in the construction of pistons and glands,.as shown in red in iig/1, described as follows: Two packing-rings S S are pressed outward against the inside of the cvlinder by the pressure of steam in a'vertical direction. T T are rings provided with recesses or steam-spacesU U, by which the amount of power pressing against such rings may he regulated according to the surface of such recesses. The amount oi" force on the outer surface of the rings S and the inner surface of the cylinder may be regulated by varying the angle of the rings S. Steam is admitted to the recesses U through small holes V V, but it may also he applied directly to the rings S, dispensingentirely with the rings T. The gland W is made substantially thesame as the piston, except that the atmospheric cir acts through the outer holes R, instead of steam.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent, is- 'lle slide-valve, constructed in such a. manner that by the aid of a ring or rings, H, provided with a fillet, N, and recess, O, the pressure of the steam on the differentwpurts of the surfaces will bc balanced, all being made and operating as herein shown and described;

THOMAS'ADAMS, [L s] n GEORGE JOHN PARSONS. [L. sf] Witnesses:

SALEM O. HARRIS, 24 Royal Exchange, London.' G. H. WYNN, 24 Royal Exchange. London.. 

